Resonant oscillatory screening device



April 18, 1961 E. J. BRUDERLEIN ETAL 2,980,254

RESONANT OSCILLATORY SCREENING DEVICE Filed Feb. 24, 1959 INVENTORS Ernst Johannes Brfiderlein Wilhelm Heinrich Rohr BY W ATTORNEY frame.

l.. J'nitecl- S ttes P? RESONANT OSCILLATORY SCREENING DEVICE Filed Feb. 24, 1959, Ser. No. 795,120

Claims priority, application Germany Feb. 28, 1958 4 Claims. Cl. 209-339 The present invention relates to a res'onantoscillating means and, more particularly, to a vibrating screen device comprising two masses oscillating in opposite directions, said masses being disposed adjacent to one another and being interconnected by springs and kinetic coupling means. stitutes the supporting frame for the other or operating mass which suitably forms a screening box.

It has been known to provide in devices of this type elastic organs, such as resilient rubber buffers, substantially in the planes of the side members of the supporting In this way, these elastic organs are readily accessible and can be easily serviced. However, the vibratory forces to be transmitted to the operating mass or screening box by means of these elastic organs react against the side members of this screening box subjecting them to high bending moments which are periodically changing. In order to be able to withstand such bending moments, these side members, the mounting means of the elastic organs, their abutment members, the transverse bars and other parts of the vibrating mass or screening box have to be made sufficiently strong which, however, increases the weight of this screening box considerably. As a result of this, the forces due to inertia and those taken up by the elastic organs are likewise increased, which is undesirable.

Therefore, it is an object of the present invention to avoid the above disadvantages and to provide a resonant oscillating device of low weight and compact construction. I 1

It is another object of the invention to provide the elastic organs in the device according to the invention in such a manner that the lines of action of these elastic organs are lying substantially in the vertical planes occupied by the side members of the operating mass or vibrating screening box.

It is further object of the invention to insert the elastic organs, such as rubber buffers, between supporting blocks mounted alternately on the upper or lower edges of the side members of the screening box and transverse bars extending alternately above or below this screening box and mounted on brackets secured to the side members of the counter vibrating mass or supporting frame.

By providing such construction, the weight of the operating mass or vibrating screening box will be considerably reduced, i.e., in some cases up to 25%. As a result of the decrease in forces due to inertia, the size and/or number of the required elastic organs can also be decreased. In this case, it is of no disadvantage that the counter vibrating mass, i.e., the supporting frame, has to be made stronger and heavier so as 'to withstand the bending forces now acting on its side members in two' directions and to support the transverse bars secured to this supporting frame, because this weight increase results in a decrease in amplitude of the counter vibrating mass or supporting frame and, thereby, of the reaction One of these masses suitably conprice 2 on its supporting springs and on the stationary base of the entire device, as desired.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific example, while indicating the preferred embodiment of the invention, are given byway of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

In the drawings:

Figure 1 illustrates a side view of a resonant vibrating screen device embodying the present invention;

Figure 2 shows a part of the swinging screen of Figure 1 in top view;

Figure 3 is a section through the screen device of Figure 2 along the lines III--III, on an enlarged scaled; and

Figures 4 and 5 are simplified diagrammatic sectional views of the prior art and of the present invention, respectively, and show the kinematics of each.

A supporting frame 2 constituting a counter vibrating mass is resiliently mounted on the ground or a relatively stationary base by means of elastic or spring means or rubber buffers 1. a This frame 2 serves to support a screening box 3 which is inserted in the frame in such a manner that sidemembers 18 of the frame 2 and respective side members 17 of box 3 are spaced from and arranged oppositely one another and are interconnected by means of inclined leaf springs 5 which are secured to the side members 17 and 18 by means of brackets 4 and 4', respectively. Transverse bars 7' anad 7' are mounted on brackets 6 and 6', respectively, which, in turn, are secured to the upper and lower edges, respectively, of the side members 18 of the supporting frame 2, said bars 7 extending above and said bars 7' extending below the screening box 3. The elastic organs, each constituting a pair of adjacent rubber buffers 9 and 10, are inserted betweenthe transverse bars 7 7' and blocks 8, 8', respectively, mounted alternately on the upper or lower edge of the side members 17 of the screening box 3. The advantage of using two adjacent rubber buffers, as opposed to a single rubber buffer which may,

\ Figures 1 and 2, are mounted on at least one of the front members -13 of the supporting frame 2. A shaft 11 is rotatably mounted in these bearings 12, this shaft 11 being parallel to the front member 13. A pulley 14 adapted to be driven by a v-belt is secured to one of the ends of the drive' shaft 11. Two eccentrics or cams 15, one of which is only shown in Figures 1 and 2, are attached to the shaft 11, each of said eccentrics or cams being surrounded by a head or follower 21 forming one 7 end of a connecting rod 22 extending into the gap'between the front member 13 of the supporting frame 2 lower transverse members 4a and 5a.

members do and 5a and the side member 18a of the, outer frame 2a so as to act in the vertical plane X of the side member 18a, as shown by arrows A. In the present invention, however, the transverse members 7 and 7 are attached to the side members 18 of the outer frame 2 and the buffers are interposed between the side walls 17 of the screening box 3, and are thus efiective, as shown by arrows A, in the vertical planeswithin which the sides of the screening box lie. One of the vertical planes is shown in Figure 5 at Y.

It will be seen from the above that according to the prior art arrangement shown in Figure 4, the oscillations of the screening box produce not only pressure forces but also bending moments B about the horizontal longitudinal axes of the side walls 17a of the box, although the whole system is in equilibrium. These bending momentsincrease and decrease periodically during operation, so that the side walls must be made sufiiciently rigid to be able to withstand the bending stresses produced by the changing bending moments. Consequently, the side walls must be made of sufliciently heavy members and this, in turn, increases the total weight of the box being vibrated. Consequently, the springs used in the apparatus must be of adequate size and strength.

In contradistinction thereto, the buffers in the apparatus according to the present inventionare arranged so as to be effective in the vertical planes Y of the side walls 17 of the screening box 3, rather than in the vertical planes X occupied by the side members 18a of the frame 2a, as was the case in the prior art device. Consequently, the buffers will produce only pressure but no bending moments whatever upon the side walls 17 of the box. As a result, the side walls 17 can be of less rigid and therefore lighter construction than the side Walls 17a of the prior art device, so that the overall weight of the mass to be. oscillated is reduced,

Furthermore, the fact that the transverse members 7, 7' are carried by the frame 2 instead of by the screening box, also contributes to the weight reduction of the box,

4. be vibrated, a frame structure somewhat larger than and around said body, said frame structure being resiliently mounted on a relatively stationary base,'means to suspend said body for vibratory movement in and adjacent said frame structure, kinetic coupling means between said body and said frame structure, said body and said frame structure forming masses oscillating in opposite directions, when subjected to vibratory actions via-said coupling-- means, a plurality of transverse bars on and across said half of each of said pairs being on top and the other half below said body, whereby said elastic organs of each pair cooperate in the oscillating directions.

2. A device according to claim 1, characterized in that each of said elastic organs comprises two pieces of a resilient material having spring properties.

3. A resonant oscillatory screening device, comprising a screening box to be vibrated, a supporting frame structure somewhat larger than and around said screening box, said frame structure being resiliently mounted on a relatively stationary base, means to suspend said screening box for vibratory movement in and adjacent said frame structure, kinetic coupling means between said screening box and said frame structure, said screening box and said frame structure forming masses oscillating in opposite directions when subjected to vibratory actions via said coupling means, a plurality of spaced transverse bars mounted on said frame structure and crossing said screening box, some of said bars extending over the top of said screening box and the others of said transverse bars extending below said screening box, pairs of elastic organs arranged between said bars and the respective sides of said screening box and being elfective in vertical planes within which said respective sides of said screening box lie, one half of each of said pairs being on top and the other half below said screening box, whereby said elastic organs of each pair cooperate in the oscillat ing direction.

4. A screening device according to claim- 1; wherein each of said elastic organs comprises two bufiers of resilient rubber facing each other in the oscillating di rection.

References Cited in'the file of this patent UNITED STATES PATENTS 2,701,061 Kluge Feb. 1, 1955 

